The invention relates to an actuating device for an electromechanically actuatable vehicle brake. Such an actuating device can be provided for actuating an electric parking brake (EPB) or an electromechanical service brake (EMB) of a motor vehicle.
US 2014/0090933 A1 discloses a disk brake arrangement having a speed reduction mechanism which comprises a plurality of spur-gear transmission stages.
In addition, WO 2012/010256 A1 and DE 10 2004 048 700 A1 discloses, inter alia, an actuating device which has a multi-stage transmission unit which is arranged between a driving electric motor and a driven drive element of the vehicle brake. In this known actuating device, the first and second stages of the transmission unit are each embodied as a spur-gear transmission and are coupled by means of a double gearwheel whose rotational axis extends parallel to the rotational axis of the electric motor. The design of such a known actuating device is explained in more detail using FIG. 1. Such a known actuating device has a compact design which results from the use of double gearwheels, so that comparatively small installation space is required.
However, owing to the compact design, the braking or tensioning forces which can be generated for the vehicle brake by means of such a known actuating device are limited upwardly. Since it is only possible to generate braking forces up to an order of magnitude of 20 kilonewtons, such a known actuating device is suitable only for use in vehicles with a weight up to an order of magnitude of 2 tonnes.